I am setting up a VMWare cluster of CentOS nodes. Is it best practice to include a domain name after the machine? What are the potential problems of leaving it out? Does a domain complicate configuration or simplify it?

For example, if my node is at 192.168.1.93, should I change /etc/hosts from

I didn't consider that point. Having a fully qualified hostname is useless for a desktop PC, and can be problematic for a laptop (because a laptop is likely to be brought in different networks) but it's useful for a server. Apache2, for example, complains when it cannot determine its FQDN.
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lgeorgetJun 2 '13 at 3:08

@lgeorget You can also just use libnss-myhostname which takes care of resolving your FQDN but doesn't need an entry in /etc/hsots
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Ulrich DangelJun 2 '13 at 7:34

The configuration above may cause problems, see this discussion on Debian’s current practice of setting up the hosts file, and this one on the usage (or lack thereof) of the localhost.localdomain entry.
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Joó ÁdámNov 4 '14 at 15:14

As long as your host agrees with your domain name, specifying it or not in /etc/hosts won't change anything. Another practice is to have it specified as the domain parameter in /etc/resolv.conf. Not specifying it could simplify your life if, one day, your network administrator changes it. Specifying it doesn't change anything, as far as I know.

You should definitely leave 127.0.0.1 localhost or 127.0.0.1 localhost localhost.localdomain in /etc/hosts. Some applications could start having a really strange behaviour is localhost binds to anything other than your loopback address because this is a really, really, unexpected setting.